[U-Boot] [PATCH v2 1/2] RFC: create u-boot-common.lds

[Troy Kisky <troy.kisky@boundarydevices.com>]

On 2/7/2012 7:24 PM, Graeme Russ wrote:
> Hi Troy,
>
> On Wed, Feb 8, 2012 at 12:56 PM, Troy Kisky
> <troy.kisky@boundarydevices.com>  wrote:
>> On 2/7/2012 6:21 PM, Graeme Russ wrote:
>>> Hi Tony,
>>>
>>> On Wed, Feb 8, 2012 at 11:49 AM, Troy Kisky
>>> <troy.kisky@boundarydevices.com>    wrote:
>
>>>> That works fine for existing sections.. i.e
>>>>
>>>> U_BOOT_LDS_SECTION(u_boot_cmd, 4)
>>>>
>>>>
>>>> but what about the next patch in the series?
>>>> Do you want me to change all lds files again?
>>> Ah, and therein lies the rub...
>>>
>>> By adding 'phy_entry' into the common lds file, you have inflicted it on
>>> everyone, and forced it to be after u_boot_cmd. What if I don't need the
>>> phy_entry section (no network support) or don't want it hard-placed after
>>> u_boot_cmd?
>>
>> Inflicted? I doubt that I added any bytes at all to boards that don't use
>> phylib.
> You are correct, it will not add anything, but we tend to have an aversion
> to dead code :)
>
>
>>>> I hope you have a better idea for how to handle patch 2/2.
>>> Add  U_BOOT_LDS_SECTION(phy_entry, 4) to all the linker scripts
>>
>> The entire reason for me for patch 1/2 was to support 2/2.
>>
>> What about  #include<u-boot-comon.lds.h>
>>
>> at the start of each lds file,
>>
>> and
>>
>> #include<u-boot-common.lds>
>>
>>
>> in the middle?
>>
>>
>>
>> If people really want to control the relative ordering of u_boot_cmd, and
>> phy_entry,
>> they are not forced to include u-boot-common.lds here.
>>
>> I can even throw in an unnecessary ifdef in u-boot-common.lds
>>
>> #ifdef CONFIG_PHYLIB
>> U_BOOT_LDS_SECTION(phy_entry, 4)
>> #endif
>>
>>
>> This will make it easier for developers to add a table without having
>> to change 192 lds files. If a few boards opt not to use
>> "#include<u-boot-common.lds>," that still means far fewer files
>> to change and less risk of typos.
> That looks like a good compromise to me
>
> As I mentioned, the U_BOOT_LDS_SECTION macro will be very useful for me
> later on
>
> The next biggie is where to define all the externs exported from the
> linker script as a result of using the U_BOOT_LDS_SECTION macro. I'm half
> tempted to think we could collect all the usages of U_BOOT_LDS_SECTION
> in a header (for the common case, that is essentially u-boot-common.lds)
> and by setting a #define you switch between full macro expansion (for
> the linker) and 'extern generation' for including in C files. That way,
> when you add a new section, everything happen automagically :)
>
> Regards,
>
> Graeme
>
So do you think this is wrong in patch 2/2?

diff --git a/include/phy.h b/include/phy.h
index bc522d5..f0eb502 100644
--- a/include/phy.h
+++ b/include/phy.h
@@ -23,6 +23,7 @@
  #ifndef _PHY_H
  #define _PHY_H

+#include <linux/compiler.h>
  #include <linux/list.h>
  #include <linux/mii.h>
  #include <linux/ethtool.h>
@@ -231,4 +232,7 @@ int phy_vitesse_init(void);
  /* PHY UIDs for various PHYs that are referenced in external code */
  #define PHY_UID_TN2020 0x00a19410

+#define __phy_entry  __attribute__((section(".phy_entry"))) __used 
__aligned(4)
+extern struct phy_driver __phy_entry_start, __phy_entry_end;
+
  #endif


I don't see how this can be automatically generated.

Troy